(a) Field
The invention relates to a display device, and more particularly to a display device which not only displays an image but also generates a sound or vibration.
(b) Description of the Related Art
A display device develops from a cathode ray tube (“CRT”) method which uses a CRT of the related art and various flat panel displays such as a liquid crystal display (“LCD”), a plasma display panel (“PDP”), an organic light emitting display (“OLED”), an electrowetting display (“EWD”), an electrophoretic display (“EPD”), an embedded micro cavity display (“EMD”), or a nano crystal display (“NCD”) have been developed.
Among the flat panel displays, the LCD which has been in the spotlight in recent years has advantages such as a reduced-size, light-weight, and low power consumption and draws attention as substitute for the CRT which may overcome a drawback of the CRT of the related art. For now, the LCD is mounted in almost all information processing equipment which requires the display device. The LCD generally includes an upper substrate in which a common electrode and a color filter are formed and a lower substrate in which a TFT and a pixel electrode are formed, and a liquid crystal material is injected between the two substrates. Different electric potentials are applied to the pixel electrode and the common electrode to form an electric field to change an arrangement of the liquid crystal molecules and adjust a transmittance of light therethrough to display an image.
In the LCD, a liquid crystal panel is a non-emissive element which does not emit light by itself so that a backlight unit which supplies light to the liquid crystal panel is provided below the liquid crystal panel.
Among the flat panel displays, an organic light emitting device has an advantage in that a light emitting diode (“LED”) which emits light by itself is provided so that no backlight is used.